Method of forming metal portions of coin collector housings



March 14, 1939. A, R, MacLAGAN ET AL 2,150,383

METHOD OF FORMING METAL PORTIONS OF COIN COLLECTOR HOUSINGS Filed April14, 193'? 2 Sheets-Sheet l fila.

V4, 9 20 g8 33 4/ a4 N @WM As @l cw mweW w .S Aff W March 14, 1939. 'ApR, MMLAGAN ET AL 2,150,383

METHOD OF FORMIG' METAL PORTIONS OF COIN COLLECTOR HOUSINGS Filed April14, 1 937 2 Sheets-Sheet 2 Patented Mar. 14, 19.39 i

UNITED STATES METHGD* F FORMING METAL PORTIONS 0F COIN COLLECTORHOUSINGS Allan R. MacLagan, Western Springs, Yand Fred F. Schuster,Berwyn, Ill., assignors to Western Electric Company, Incorporated, lNewYork, N. Y., a corporation of New York IApplication April 14, 1937,Serial No. 136,760

6 Claims'.l (Cl. 25J-148.2)

This invention relates to a method of forming metal articles, and moreparticularly to a method Y of producing the front portion of the lowerhousing for telephone coin collectors.

Telephone pay stations at which coins are deposited by the user inpayment for completed calls are provided with receptacles for receivingthe deposited coins. In some cases stations of this type are located inpublic places where there is no attendant. The door of the coinreceptacle is exposed and unscrupulous persons sometimes break into thereceptacle by prying oif the door or cutting away, or otherwise removinga dish shaped front portion of the lower housing, which supports thedoor to the coin receptacle.

In the usual type of telephone coin collector as disclosed in the O. F.Forsberg U. S. Patent 1,043,219, issued November 5, 1912, the coinreceptacle occupies most of the lower housing of the collector exceptfor the coin return opening on one side thereof. It has been customaryas shown in the F. A. Hoyt Patent 2,025,390, issued December 24, 1935,not to use hinges for the coin receptacle door,`but to form integralwith the door a lug extending substantially across the bottom end of thedoor and forming with the main edge of the door an elongated slotadapted to it over the lower edge of the coin receptacle opening, whichis formed in the front portion of the lower housing. This lug isreinforced by a plurality of vertical ribs integral with the door andextending between the lug. The top of the door is usually held inposition by `the bolt of a lock which engages a lock lug securedadjacent the upper edge of the coin receptacle openprises a single pieceof drop forged steel suitably heat treated to give it a high degree ofhardness and toughness. It is, therefore, desirable that the dish shapedfront portion of the lower housing which supports the door be also asstrong as possible and so formed with respect to the door and its lugand ribs which fits the opening in the housing that it will be verydifficult to cut Yit away or otherwise remove it in attempting to gainaccess to the coin receptacle.

It has been the practice to form the dish shaped lower front housingportion from mild pressed steel formed to a desired configuration withthe' outer and inner surfaces of the side walls of the housing disposedat right angles to the face supporting the door and its outer surface inthe plane of the sides of a rear portion of the lower housing, but 'suchsteel is not so Vcapable of reing. The door with its integral lug andribs com- Y sisting attack as the drop forged door itself. It

has also been propose-d to make the lower front housing portion of dropforged steel, but with the various associated assemblies carried withinthe housing being so compactly arranged, a substitution of a drop forgedfront for a .pressed steel front necessitates that the drop forged fronthave f substantially the same dimensions and configura- Vtheprior designof standar-d mechanism housed therein, by drop forging it has been orwould have been necessary to remove by multidous and costly cuttingoperations this inner and outer excess metal. Another dicultyencountered was in forming clearances in the bottom wall of the proposeddrop forged front for the vertical ribs on the door.

An object of the present invention is the provision ofY an eiiicent andpractical method of producing metal articles, and more particularly tothe working of such drop forged dish shaped front portions of the lowerhousings of telephone coin collectors Vwhereby the difficulties abovementioned are overcome.

In accordance with the above object, the invention as applied to formingthe lower front housing portion of a telephone coin collectorcontemplates a method which comprises forming by drop forging adishshaped blank with a desired inner and outer configuration except thatthe top,

The blank with theparting line at the rear edge is then forcedthrough areforming punch and die mechanism to remove the inclination of the wallsv front portion in flush and abutting relation. A further step comprisesmilling a door Seat around the door openings.

Other objects and advantages of this invention will more fully appearfrom the accompanying detailed description taken in connection with theaccompanying drawings, wherein Fig. 1 is a plan view of a drop forgeddish shaped blank for the lower front housing portion of a telephonecoin collector;

Fig. 2 is a fragmentary front elevation of the blank illustrated in Fig.1;

Fig. 3 is a diagrammatic fragmentary View, partly in section, of areforming punch and die mechanism illustrating the step of removing theoutward inclination of the four sides of the drop forged blank:

Fig. 4 is a front elevation Aof `the blank upon completion of the stepillustrated in Fig. 3, and after successive forming and perforatingoperations to provide' clearances in the bottom wall for the door ribsand in the front wall thereof for the door and coin return openings;

Fig. 5 is a horizontal section taken on the line 5 5 of Fig. 4;

Fig. V6 is ka'vertical .section taken on the line 6--6 of Fig. 4Vshowing the blank'at the completion of a further step of milling a doorseat around the opening for the door;

Fig. '7 is a front elevation of Fig. 6 showing the housing uponcompletion of further steps of milling the outer, top, bottom, and sidewalls and a continuous shoulder adjacent their rear edges to receive therear housing portion which is spot welded thereto in flush and abuttingrelation;

Fig. Sis a vertical section taken on the line 8 8 of Fig. 7 showingdiagrammatically the step of simultaneously milling the top and bottomside walls and the forming of the shoulders at their rear edges on thehousing to receive the rear housing portion, the opposite side wallsbeing milled in a similar manner;

Fig. 9 is a side view of a telephone coin collector having a drop forgedlower front housing portion produced in accordance with the method ofthis invention spot welded to the -rear lower housing portion, and

Fig. 10 is an enlarged fragmentary horizontal section taken on the lineIII-I0 of Fig. 9.

Referring now to the drawings and particularly to Fig. 9, there isillustrated a telephone coin collector which includes a mounting or baseplate I4 and a rear portion of a lower housing I5, a drop forged lowerfront housing portion produced in accordance with the method of thisinvention and spot welded to the rear portion of the lower housing beingindicated at I6. An upper housing portion I'IV whichv carries well knownmechanism completes the housing for the telephone coin collector.

In producing the housing portion I6 a slab of steel of requisitedimensions is formed into a dish shaped blank I9 having front, top,bottom and opposite side walls 20, 2I, 22, 23 and 24, respectively,(Figs. 1 and 2) by drop forging in a well known'manner. The blank I9upon completion of the drop forging operation will have a desired innerand outer configuration, except that the top, bottom, and opposite sidewalls are inclined outwardly in order that the blank may be readilystripped from the forging ram after the forging operations.

`The blank I9, upon completion of the forging operations, referringparticularly to Figs. 1, 2, 4 and 6, includes a notch 21 formed in therear edge of the top wall 2I for freely receiving a part of an assemblydepending from the upper housing portion I'Lthe notch having adepression 28 providing a clearance space for a part carried in thelower rear housing portion I5. Formed on the inner surface of the frontwall 20 is a vertical reinforcing rib and foundation 29 for a partitionmember subsequently welded thereto. Also formed on the inner surface ofthe front wall 20 is a projecting two part lock bolt strike 3l), thelower edges of which, as shown in Fig. 4, are in line with the upperperipheral wall of the door opening. No further reference to the abovedescribed formations', 28 and 23 on the blank I9 will be made except indescribing hereinafter an .operation on the lock strike 3B.

After the blank I9 has been formed, as shown Vin Figs. 1 and 2, itisplaced in a reforming punch and die mechanism (Fig. 3), the blankresting in a forming aperture 33 of a die 34 for operation upon by areciprocating shouldered punch 35. The dieaperture 33 and punch 35 havea desired configuration and are otherwise suitably shaped to operateupon the walls 2i, 22, 23 and 24 to remove the outward inclinationthereof without deleterious injury to other portions of the blank. Thedie 34 ynormally rests by gravity upon a bed 36 rand has a limitedvertical movement thereon during the operation of the mechanism. Aplurality of screws 31, two of which are illustrated, are threaded attheir lower ends into the bed 36, the headed upper ends of the screwshaving a sliding fit in shouldered apertures in the die 34. The upwardmovement of the die 34 is limited by the space between the lowersurfaces of the screw heads and surfaces 40 of the shouldered aper-Reciprocally carried in opposite recesses in the upper surface of thebed 33 are spring pressed stripping plungers 4I having inclined faces attheir inner ends which normally are pressed outwardly by an auxiliarymanually slidable bed plate 4Z carried in a continuous channel 43 in thebed 36, the inclined end faces of the plungers engaging opposite sidesof the plate. Opposite sides of the plunger recesses are provided withslideways in which ride dovetails formed on the plungers 4I effective toprevent the plungers from moving upwardly, the slideways and dovetailsbeing indicated by the broken lines 44.'. Pins 47 fixed in the bed 36and extending into slots in the plungers 4I are effective to limit theinward movement of the plungers during the operation of the mechanism.

In reforming the drop forged blank I9 the punch 35 descends, engages theinner surface of the front wall 20 of the' blank, and at the end of itsstroke has forced the blank partly through the die aperture 33, andagainst the upper surface of the auxiliary bed plate 42 to the positionindicated in broken outline by the numeral 48. In passing along the dieaperture 33, the inclined walls 2|, 22, 23 and 24 of the blank i9 willbe .drawn inwardly and formed at right angles to the front wall 2G andat the same time there will be a slight unavoidable bowing outwardly ofthe front wall 2l) which is flattened or swaged at the Vtermination ofthe described stroke of the punch the 'other Vopposite side walls of theblank below ,76

the die also being spaced and free from any coniining walls. Thisspacing of the lower periph- `eral surface of the blank I9 from anywalls of the .mechanism permits a free necessary slight flow of tionupon the blank I9 indicated by the dotted outline position 48 thereof,the ram 35 is elevated a slight distance and due tothe frictionallocking grip between the peripheral surface of the reduced shoulderedlower end of the ram and the inner surface of the blank and that betweenthe outer surface of the blank and the inner surface of the die aperture33 the blank and the die 34 are likewise elevated, the die sliding onthe screws 31. The described unitary movement of the ram, the blank, andthe die is for the purpose of removing the pressure of the blank uponthe slidable bed plate 42 and such movement need only be a very'slightdistance and, therefore7 no strain is put on thescrews 31.

With the blank I9 thus elevated, the bed plate 42 is slid in the channel43 of the bed 36 from under the blank by means of a handle 49. Themovement of the bed plate 42 permits the spring pressed strippingplungers 4I to move inwardly and their inclined inner end faces engageopposite walls of the blank. Thereafter the-ram 35 carrying the blank I9and the die 34 is caused to descend again, the die being returned to itsnormal position in engagement with the upper surface of the bed 35 andin the continuing movement of the ram the blank is carried through thedie aperture 33 and downwardly until the upper edges of the Walls ofthe'blank are sufciently below the lower surfaces of the strippingplungers 4I to permit the latter to move thereover. In this position ofthe ram 35 the large upper end thereof has freely entered into the dieaperture 33 and is located below the plane of the lower surfaces of thestripping plungers. To permit the stripping plungers 4I to move to thedescribed position over the upper edge of the i blank the ram is notchedin line with the plungers as indicated in dotted outline at 59.

The ram 35 is now caused to ascend to its normal upper position duringwhich movement the reformed blank I9 is stripped from the ram by theplungers 4I being engaged with the upper edge of the blank and it fallsto the bottom of the continuous channel 43 of the bed 36 to the positionindicated in dotted outline` by the numeral 5I. The blank may then beslid out of the channel 43 by moving the bed plate 42 back to its normalposition. During the latter movement of the bed plate, cam faces, shownin dotted outline at 54, on the advancing forward end of the plateengage the inner ends of the stripping f plungers and move theminwardly'to their normal positions. The bed plate 42 is of suchlengththat when it is in its normal position the cam faces 54 thereof will belocated beyond the path of the blank I9 while it is being forced throughthe die by the ram 35 and during the flattening of the front wall 29 ofthe blank by striking it against'the upper surface `of the bed plate.The side walls 2l, 22, 23 and 24 of the blank I9 upon being removedfromthe reforming punch and die mechanism will be formed at Vrightangles to the front wall 20, as shown in Figs. 4 and 5.

Following the above described steps of the method three depressions 51(Figs. 4 and 6) serving as clearances for the vertical door ribs areformed in the inner surface of the bottom wall 22 of the blank I9. Thedepressions 51 are simultaneously formed by suitable cooperating swagingdies arranged at opposite sides of the wall of the blank which duringoperation thereon permit the excess metal displaced or extruded inform-'- ing the depressions to flow outwardly to form embossments 58 onthe outer surface of the wall 22 which are subsequently removed. Thusthe `depressions 51 are formed without any deleterious .distortion ofthe wall of the blank.

In a subsequent step of the method the front wall 20 is perforated at 59and 60 (Figs. 4 and 6) in a single operation to provide openings for thedoor and coin return openings.

In a succeeding step of the method the projecting two part lock boltstrike 3l) is bumped or swagedupon upper surfaces 6I thereof, as viewedin Fig. 5, such surfaces being disposed at right angles to andterminating at their lower edges, as shown in Fig. 4, with the upperperipheral wall of the door opening 59. The purpose of swaging the lockstrike surfaces 6I is to flatten them, thereby removing any unevennessthereof resulting from the forging operations or distortion occurringduring the perforating of the front wall in forming the door opening.

A further subsequent step of the method consists in bumping or swagingslight depressions or clearances 62, indicated in dotted outline, in theinner surface ofthe front wall 29 at opposite ends of the coin returnopening 50 (Fig. 7) for receiving Iianges of an-escutcheon plate (notshown) which in the final assembly of the coin collector surrounds theopening.

In successive subsequent steps of the method the outer surfaces of thefour side walls are subjected to milling operations to trim them of un-yranged to simultaneously mill the top and bottom side walls 2l and 22,respectively, and form the shouldered surfaces 65 in one operationacross the blank I9. In another operation the side walls 23 and 24' aresimilarly milled. Following the above vdescribed milling operations theblank I9 in another step is caused to rotate past a milling cutter toremove the metal remaining at the four corners of the blank, indicatedat 68 (Fig. '1), at the termination of which operation a continuousperipheral shoulder is formed on the blank. Y

The next step of the method comprises forming,`preferably by a millingoperation, a continuous depressed door seat 69 (Figs. 6, 7 and 8) in thefront wall 29 of the blank I9 around the door opening 59. This is thefinal step in the method of producing the drop forged dish shaped frontportion I6 of the lower housing of telephone coin collectors describedabove with the exception of minor operations, such as surface grindingand finishing operations.

It is believed that the method of this invention will be fullyunderstood from the above description, and it will be seen that itproduces important advantages in the art of working drop forged dishshaped blanks to remove the normal inner and outer outward flare of theside of the blank, and particularly to an efcient and practical methodof working such blanks to produce front portions of the lowerV housingsfor telephone coin collectors.

While the method of this invention has been disclosed and described inconnection with drop forged dish shaped front portions of the lowerhousings for telephone coin collectors., it will be understood that theinvention is capable of application to other types of drop forged dishshaped articles and is only limited by the scope of the appended claims.

What is claimed is:

1. The method of producing the lower front housing portion of telephonecoin collectors comprising forming by drop forging a dish shaped blankhaving front, top, bottom and side Walls with a normal outward flare ofthe top, bottom and side walls, forcing the blank partially through adie to form said latter walls at predetermined angles to the front wall,swaging the front wall to flatten it at the termination ofthe top,bottom and side wall forming movement,

forming depressions in the inner surface of the bottom Wall to provideclearances for door ribs, and cutting openings in the front wall for thedoor and coin return.

2. The method of producing the lower front housing po-rtion of telephonecoin collectors com.- prising forming by drop forging a dish shapedblank-having front, top, bottom. and side Walls with a normal outwardare of the top, bottom and side walls, forcing the blank partiallythrough a die to form said latter walls at right angles to the frontwall, swag-ing the front wall to flatten it at the termination of thetop, bo tom and side wall forming movement, forming depressions in theinner surface of the bottom wall to provide clearances for door ribs,cutting openings in the front wall for the door and coin return, andshaping the top, bottom and side walls at their rear edges to fo-rm` acontinuous shouldered surface to receive a rear housing portion.

3. The method of producing the lower front housing portion of telephonecoin collectors comprising forming by drop forging a dish shaped blankhaving front, top, bottom and side Walls with a normal outward flare ofthe top, bottom and side walls, forcing the blank partially through adie to form said latter walls at right angles to the front wall, swagingthe front wall to atten it at the termination of the top, bot- Ytom andside wallV forming movement, swaglng depressions in the inner surface ofthe bottom lwall to provide clearances for door ribs, perfothe blankpartially through an open die with the edge of the side thereof trailingto form the side at a predetermined angle to the face thereof thenswaging the face to flatten it at the termination of the side formingmovement, the face `and the adjacent portion of the side being freelyspaced from the die during the swaging of the face to permit the metalto flow toward the periphery of the blank, and subsequently forcing theblank completely through the die.

5. The method of producing the lower front housing portion of telephonecoin collectors comprising forming by drop forging a dish shaped blankhaving front, top, bottom and side walls with a normal outwardinclination of the top, bottom and side Walls forcing the blankpartially through a die with the edges of the walls trailing to formsaid latter walls at predeter- Y mined angles to the front wall, swagingsaid front wall against a movable die bed plate to flatten it at thetermination of the wall forming movement, the front wall and theadjacent portions of the walls being freely spaced from the die duri ingthe swaging of the front wall to permit the metal to iiow toward theperiphery of the blank, relatively moving the blank and the movable diebed plate to relieve the pressure therebetween, moving the die bed plateout of the path of the blank, and subsequently forcing the blankcompletely through the die.

6. 'Ihe method of producing the front housing portion of coin collectorscomprising drop forging a multi-sided blank having outwardly flaringsides, forcing the blank partially through an open die to form the sidewalls at predetermined angles to the face of the dish shaped article,swaging the face to insure its flatness, and subsequentlyforcing theblank completely through the die.

ALLAN R. MACLAGAN. FRED F. SCI-IUSTER.

